JPS60125646A - Manufacture of laminated body containing metal foil - Google Patents

Abstract

PURPOSE:To efficiently manufacture a laminated product of a satisfactory strength of adhesion without deformation and other defects of a film by laminating a metal foil and a thermoplastic synthetic resin, by forming laminated product by directly supplying the metal foil with electricity and heating it. CONSTITUTION:The material 7 which has a metal foil 5 and a polyolefin 6 that are laminated is sent over to the metal rolls 1 and 2 through a roller 8 and the metal foil 5 which has electrical conductivity is supplied with electricity by the electrodes of the metal rolls 1 and 2, resulting in heat generation of the metal foil 5 and the foil is heated. At this time a voltage of the power source of less than 30 volt is desirable for safety voltage. As stated above, by applying a low voltage of electricity directly to the metal foil as a heat generating body, a hight temperature heating adhesion becomes feasible and a laminated product which has a thin metal foil and a thermoplastic resin that are laminated together may be obtained.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a laminate including metal foil.

One method for manufacturing a laminate containing metal foil is to use a heated roll. This is done by heating metal rolls with steam, etc., and then heating the metal rolls between the heated rolls.

This is a method of making a laminate by passing through a metal foil and another sheet such as a plastic sheet, and bonding them under heat and pressure. However, with this method of indirectly applying heat to the metal foil or the like via the heating roll, it is necessary to take a long heating time in order to bond the gold MWi and the plastic sheet well. For this purpose, it is necessary to increase the diameter of the heating roll or to slow down the take-up speed. However, if the diameter of the heating rail is increased, the equipment will not only be large and expensive, but also the size of the heating roll may have problems in processing, surface temperature distribution, etc. , subject to constraints. In addition, a decrease in take-up speed poses problems in terms of productivity and economy.

On the other hand, there are methods that use heating furnaces, hot air dryers, etc.
A laminate of uniform thickness could not be obtained due to thermal deformation or contraction of the plastic layer or metal foil;
In this method, since the entire bonded body must be heated, heating takes a long time, the processing speed is slow, it is not economical, and the adhesive strength is not sufficient.

Furthermore, there is also a method using high frequency heating. This method involves passing a high-frequency current through an induction coil, inducing the current through a metal foil,
A method for dielectrically heating metal foil, for example, Japanese Patent Application Laid-Open No. 54-4
Publication No. 8868 discloses that a conductor is placed on both sides of the surfaces to be bonded between opposing materials such as a foil and a thermoplastic synthetic resin layer, and a high-frequency current is passed through the conductor as a reciprocating wire ring, and the bonding is performed by induction heating. The method for performing this is described, and also published in
No. 827 discloses that by sandwiching a plastic layer between two metal foils and passing the plastic layer near an induction heating coil,
The two gold JIs mentioned above! A method is described for bonding two metal foils and a plastic layer by high-frequency induction heating of the foils.

However, in general, with dielectric heating methods, it is difficult to maintain uniformity of temperature on the heating plane, and it is necessary to use an auxiliary heating method.Also, since high-frequency induction is used, the design and equipment are designed with safety in mind. is especially necessary.

The present invention relates to an improvement in the bonding method for laminates containing metal foils that are relatively far apart for good adhesion. The thermoplastic synthetic resin is laminated and bonded to the metal foil as a heating element, and the metal foil is heated uniformly, and the surface of the resin layer that comes into contact with the metal foil is melted and adhered. By adjusting the current between the electrodes, the resin layer is melted at once, so a laminate with good adhesive strength can be produced without deforming or shrinking the film, increasing the processing speed. succeeded in doing so.

Next, an example of a method for manufacturing a laminate including metal foil according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, an electrode 1 and an electrode 2 are placed at an appropriate interval, and one end of the electrodes 1 and 2 is connected to a power source (AC power source) 4 via a transformer 3. In FIG. 1, 30 indicates the secondary side and 31 indicates the primary side transformer winding.

For the electrodes 1 and 2, metal tubes can be used as shown in FIG. Note that the distance between the nuclear electrodes is, for example, about 1 m.

A material 7 in which a metal foil 5 and a polyolefin film 6 are superimposed is fed onto such metal rolls 1 and 2 via a feed roller 8, and electrical conductivity is achieved using the core metal rolls 1 and 2 as electrodes. When a current is passed directly through the metal foil 5, the metal foil 5 generates heat and becomes a heating body.

Good results can be obtained by using a low power supply voltage that has little effect on the human body and a high current.

In general, metal foil has a low electrical resistance, so it is dangerous to use normal voltage, and it may melt instantly if a large current flows through it. From this point of view, the safe voltage is preferably 30V or less.

In this way, by directly passing a low-voltage current through the metal foil, it is possible to use the metal foil as a direct heating element to perform high-temperature heat bonding. A bonded laminate is obtained.

The metal foil used in the present invention needs to be electrically conductive, and most metal foils are usually electrically conductive. A specific example of metal foil is aluminum foil (hl! foil).

The thermoplastic synthetic resins used in the present invention include various types such as polyolefin, polyamide, polyester, etc. Even thermoplastic synthetic resins such as polyolefins, which are considered difficult to adhere to metals, can be used successfully according to the present invention. Can be adhered to.

The laminate containing metal foil according to the present invention is composed of a layer made of metal foil and a layer made of thermoplastic synthetic resin, so that better adhesion is achieved between the metal foil and the thermoplastic synthetic resin. An adhesive may be used for smoothing. As such an adhesive, acid-modified polyolefin is preferably used.

Here, acid-modified polyolefin refers to polyolefin containing one or more alicyclic carboxylic acids having a cis-type non-conjugated double bond in the ring, α, β-unsaturated carboxylic acids, or anhydrides thereof. It refers to a modified polyolefin obtained by chemically bonding the following, and a modified polyolefin produced by a modification method such as that described in Japanese Patent Publication No. 56-9925 can also be used.

By using such an acid-modified polyolefin as an adhesive, it is possible to improve the adhesion between the metal foil and the nonpolar polyolefin that does not have a polar group in its polymer chain.

In the present invention, in addition to laminating and adhering such metal foil and thermoplastic synthetic resin with or without an adhesive, a laminate including at least two or more layers of metal foil can be formed, such as by interposing paper in the middle. All that is included is included.

In the present invention, a laminate is obtained as described above by passing a low-voltage current through the metal foil, but if necessary, the laminate may be pressurized to further improve adhesive strength.

For example, as shown in FIG. 1, a pressure roll such as a silicone rubber shank roll 9 may be placed on the metal roll electrode 2, and the laminate may be passed between these rolls and crimped, or the laminate may be crimped using a press or the like. It's okay.

Alternatively, it is also possible to extrude a thermoplastic synthetic resin using an extruder, superimpose it on a metal foil, heat the metal foil by passing an electric current through the metal foil, and press the resin.

According to the present invention, ■ By passing a low voltage and high current through the metal foil, the metal foil is uniformly heated and the surface layer of the thermoplastic synthetic resin film is melted, thereby creating a laminate containing gold R foil with improved adhesive strength. is obtained.

By using an adhesive as necessary and bonding under pressure, a laminate with increasingly improved adhesive strength can be obtained.

■ Continuous processing is possible because the metal foil is directly heated; the metal foil is heated, and the heat melts the laminated film and melts it instantly; - No shrinkage or deformation. That is, in the conventional indirect heating method, for example, the metal layer is heated by heat from the heating roll surface, and it takes a long time to heat the laminated film until it melts.

Excessive heating previously caused shrinkage and deformation of laminated films, but this can be avoided.

(2) Since current is passed through a thin foil body such as metal foil, the heating time is fast and the processing speed is fast, making it suitable as a method for manufacturing laminates containing metal foil. Since the current only needs to be passed through a thin metal foil, a low-voltage power source can be used, thereby avoiding any effects on the human body.

- Since a current is passed directly through the gold R foil, the temperature distribution of the metal foil tends to be uniform, and it is easier to maintain temperature uniformity compared to high frequency conducting heating.

■ A general metal roll can be used as an electrode, and the heating temperature and melting temperature can be adjusted arbitrarily by adjusting the current and voltage.

Next, an example of the present invention will be shown.

Examples 1 to 10 8- (1) Aluminum foil surface temperature measurement Using the apparatus shown in Fig. 1, an 85φ metal roll electrode and an 85φ
The distance between the electrode and the metal roll electrode is set to 1m, and the
I connected the 00V slider to the 24V power transformer.

Aluminum foil with a thickness of 9 μm and a width of 1 octn was placed on all of these rolls.

Next, Al passed a current through the foil while turning TOOV's Sushi Duck, and measured the surface temperature of the aluminum foil using an infrared thermometer.

The results are shown in Table 1.

Table 1 *Temperature rise at the start of energization (in seconds) (2) Adhesion test Using the above apparatus, a laminate consisting of the following film composition was made. The laminated film has a width of 15118 mm and a length of 15 cm.
rn was removed and 180° peeling was performed.

The results are shown in Table 2.

Film composition ※■GPP50μ/MA-PP 10μ/mu foil 9μ※■O
PP: Cast film of ethylene a-pyrene block copolymer MA-PP; Maleic anhydride modified polyp-pyrene (MI (230°C) = 21.6# 710 minutes) Table 2 Example 11 The film composition is as follows. A laminated film was prepared in the same manner as in Example 6 except that the 1800 peel test was conducted in the same manner. The results are shown in Table 3.

Film composition *■M A-LDP [C: Maleic anhydride-modified low-density boron 11-rietitanium Table 3 □□” Example 12 A laminated film was produced in the same manner as in Example 7 except that the film composition was changed to the following. , 1800 peel test was conducted in the same manner. The results are shown in Table 4.

Film composition: High-density polyethylene cast film MA-LDPIE: Maleic anhydride-modified low-density polyethylene 12- Table 4 Example 13 A laminated film was produced in the same manner as in Example 11 except that the film composition was as follows. was prepared and similarly subjected to the 1800 peel test. The results are shown in Table 5.

Film composition wide■MA-HDPIC1011/At foil 9μ※■Mmu HD
Pg: Maleic anhydride-modified high-density polyethylene Table 5 Example 14 A laminated film was prepared in the same manner as in Example 13, except that the film composition was as follows, and a peel test was conducted in the same manner. The results are shown in Table 6.

Film composition (2) HDpx A laminate of opp soμ/Mmu-PP 10μ/ml foil 9μ similar to that in Example 3 was produced by pressure bonding between heated rolls at a roll temperature of 120C. The pressure applied by the heating roll was a linear pressure of 10 kfZm.

The results are shown in Table 7.

Table 7

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the manufacturing method of the present invention. 1...All categories (electrodes) 2...Metal rolls (electrodes) 5...Metal foil 6...Thermoplastic synthetic resin (film) Patent applicant Toa Fuel Industries Co., Ltd. Representative Patent Attorney Yoshihiro Sato

Claims (1)

[Claims] 1. A laminate including a metal foil characterized in that when manufacturing a laminate including a metal foil layer and a thermoplastic synthetic resin layer, the metal foil is heated by directly passing an electric current through the metal foil. Production method. 2. The manufacturing method according to claim 1, wherein the thermoplastic synthetic resin is a polyolefin film. 5. The manufacturing method according to claim 1, wherein the laminate including the metal foil is a laminate having a structure in which a thermoplastic synthetic resin is laminated and bonded onto the metal foil via an adhesive. 4. The manufacturing method according to claim 5, wherein the adhesive is made of acid-modified polyolefin.